Last year I filed all my deductions from renovating and selling an apartment online. There's a fair amount of functionality now (according to the FAQ selling forest, business income, house/apartment sales (K2,5,6) investments (K4) et c) can be done online.

The swedish tax authority also incentivizes people to e-file: if you e-file, you'll get your tax return before midsummer, which in Sweden is a BIG holiday, when most people kick off their summer vacation. Even if you accept the defaults, but file on paper, you'll get your money in August instead of June.